Parameters:
action='/' - that parameter's value ia standard, it's an ordinary reference to our system.
<input type=hidden name=a value="input"> - means that this is the input form.
<input type=hidden name=err_tpl value="guestbook-add_mes"> -
sets template's name, which will be output in error.
Optimal if that template coincide with input form template.
Later we'll say how to transmit already input parameters to that template.
<input type=hidden name=ok_tpl value="guestbook-ok"> - template's name will be output in case if input operation is success.
<input type=hidden name=act_tpl value="guestbook-actions-add_mes">
- script of data input. See below how to describe script of input.
<input type=hidden name=res_link value="/guestbook"> - link of changeover. If template "ok_tpl" would be used for different actions it is possible to indicate diferent adresses for changeover. Example:
"/guestbook" if it is ususal user and "/guestbook-admin" for administrator.

Files from the folder "templates" could be templates for html-documents and scripts executable by ReJump system. It is impossible to use html-tag in script. You can use only conditional transfer operators and ReJump functions.

add() - adds empty object with extension "mes" in folder "data-guestbook"
update() - enter and renew information
in "$i.Message" - text which was input in the field "Message"
("$i" - indicates an input form; "$i.Message" - parameter of form with name "Message")
Parameter "Text" in "update" function points to file contents. In that case contents of new file which name is in the variable "add_name".